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Is sugar addictive?

How hazardous is sugar, and would a move to plain wrappings on sweet treats ease our health crisis?

“The fun police are at it again,” opined talkback radio, “and just before Christmas, too.” Yes, Northland DHB chief executive Dr Nick Chamberlain made the argument for plain packaging of sugary treats (and, to be fair, high fat and salt products, too). The base argument was that we live in an environment where it’s too easy to make the wrong decisions, so let’s level the playing field just as we did with cigarettes.

According to Stuff, Brent Baillie of Rainbow Confectionary said in response, “Cigarettes are an addictive item, lollies aren’t. Cigarettes have addictive chemicals in them that influence the brain, lollies don’t.”

But how true are these competing claims? Should we be drawing comparisons between snorting cocaine, sucking on a cancer stick and scoffing half a big bar of Whittaker’s?

There are several ways to look at this. These include considering whether sugar affects our brains and how similar any effects might be to drugs of abuse, and whether sugar is addictive in similar ways.

Take cocaine as an example. It is quickly absorbed past the blood-brain barrier and, among other things, hitches a ride on your brain’s dopamine transport system. Dopamine is one of those “pleasure” chemicals that are released when something good happens. But they’re supposed to go home once their purpose has been satisfied, and they can’t do that when the buses home are all full of cocaine. The party goes on until the buses empty out.

Consuming sugar doesn’t block the re-uptake of dopamine in the same way as cocaine, but it does affect our central nervous system (of which the brain is a fairly big part) in at least two ways. First, through our sensory system – triggering taste cells in our guts and mouths. Why? Because over a long, long timescale, our taste system has adapted to expressly value sugar as a source of energy. During that evolutionary timescale, though, sugar wasn’t as readily available as it is now. Our ability to manufacture easy energy has outstripped our need to run away from toothy carnivores.

Sugar also affects how our central nervous system manages “glucose homeostasis” – calibrating blood sugar levels to what’s actually needed. A flood of sugar can upset this delicate balance and trigger a cascade of issues that can end in obesity or diabetes.

So, sugar works differently, but I’m not sure that’s a good argument for dismissing the sugar-as-drug analogy. Nicotine doesn’t exactly hijack the dopamine system as cocaine does, either, instead bearing more similarity to how morphine or heroin work – by increasing the release of our brain’s natural painkillers. We wouldn’t say that nicotine is okay for us, either.

Cocaine and nicotine are, however, clearly addictive in the way that we typically think about addiction – users both crave these substances and suffer unpleasant effects when they can’t get them. Subjectively, the craving for sugar appears to be, for at least some of us, as strong as the craving for nicotine or cocaine.

I can’t imagine we’ll ever see this kind of experiment with humans, but, given a choice, rats will pick sugar over cocaine and nicotine in drug self-administration studies. Neurochemically, sugar “withdrawal” also shares a similarity with heroin withdrawal, just not as intensely.

In fact, that’s kind of the lesson of the day. Sugar gives us a boost, just not as strong a boost as nicotine or cocaine. It affects our central nervous system, just not as much as drugs of abuse. It has similar neurochemical withdrawal, but it’s weaker. Where it does seem to be stronger is in terms of the natural preference.

Where they are clearly and importantly different is in what happens if you acutely overdose. Cocaine will kill you much faster than sugar. What the Northland DHB is pointing out, though, is that morbid obesity and diabetes can kill you, too, just much more slowly.

This article was first published in the January 18, 2020 issue of the New Zealand Listener.

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